1. Field of Invention
The present invention relates to separation of viscous source materials, and more particularly, to methods and systems for optimization of dilution of a viscous starting material to isolate and/or concentrate the product of interest from the starting source material such that the process minimizes the volume of diluent and the total volume of the waste stream generated as well as maximizing the yield of desired product.
2. Discussion of Related Technology
Throughout the world more and more companies are looking to recover value added products from a wide variety of starting materials including plants, roots, root crops, grains, flowers, animal tissue, cell cultures comprising yeast, algal, bacteria, or fungi species, milk, milk products, fruits and fruit juices. Additional companies are looking to extract value added products from solid and liquid waste streams such as mill and grain wash waters and fermentation bio-mass. One such waste stream will be the bio-mass from bio-fuel production which after production of fuels such as diesel and alcohol will still be rich in plant proteins, sugars and carbohydrates. Another such waste stream will be cellular bio-mass used for protein and essential fatty acids production from wild and/or recombinant yeast, algae, bacteria, larvae or fungi species.
A common practice for dry or solid starting materials is to solubilize starting materials in a solvent such as aqueous and organic solvents so that the valuable component becomes soluble in the solvent. The solution is then processed by one or more of the known techniques of filtration, precipitation, extraction, chromatography and centrifugation to separate the valuable components from the starting material and solvent. As a result of growth in demand for naturally derived products companies are increasing production of these products. Production costs and environmental issues such as the release of contaminated liquid waste streams have pressured companies to extract more of the final product from the starting material and to minimize the use of solvents by preparing larger more viscous process streams.
In recent years the science of cell culture has also endeavored to increase production of cell derived products such as antibiotics, vaccine and therapeutic compounds by increasing the density of the cell cultures utilized to produce these highly valuable materials. Increased cell density can be a highly beneficial as it allows for the increased production of the final product in the same space as a less dense cell culture. It would seem that doubling the concentration of a cell culture forming a viscous material should yield twice as much final product without any substantial increase in fermentation facility costs.
However, it has been found that all of these highly viscous materials are far more difficult to process, such that, even though the cell culture is five (5) times denser the yield of final product is only 50% greater because the viscosity of the material prevents the separation of the desired target molecule from the mass of cellular materials. In the case of extracts of solid phase material such as plants and animal tissue the problem is the same such that the viscous materials clog filters and block chromatography columns as well as not separating efficiently under normal centrifugal forces. One way of describing the problem is to say that although larger crowds would contain more people able to buy a particular good or service it is harder to get the people with money through the stores doors due to the congestion caused by the crowd itself.
Although it would appear that a simple dilution of the viscous material would solve the problem, this creates at least four additional problems: 1) the cost of the diluent which can be highly expensive in the case of diluents for pharmaceutical intended for human injection, 2) disposal of the higher volume of the waste stream, i.e. the original volume plus the volume of diluent, 3) the cost of the necessary tanks and mixing equipment in order to dilute the starting material, and 4) additional purification costs for the diluted final product.
As important as these problems are the single most important point is to have the highest percentage of yield so that the initial purpose of processing higher density materials is not negated by problems with recovery of the desired product. Thus, it would be advantageous to provide a method and system that provides higher yields from high density materials.